Are you installing over an existing dir /usr/src/linux-2.4.18/.... as none root user the problems seem to be that mkdir doesn't succeed instead of too little space. It just gives the wrong response because it can't create the dir it assumes that the disk is full. Another problem can be your inode count (using ext2 / ext3). every file / dir / link needs an inode. You can check this by using tune2fs -l /dev/hda6.

Hope it helps, lX

Ps: what filesystem are you using?_________________"Remember there's a big difference between kneeling down and bending over.", Frank Zappa